Oxidative/Nitrative Stress and Inflammation Drive Progression of Doxorubicin-Induced Renal Fibrosis in Rats as Revealed by Comparing a Normal and a Fibrosis-Resistant Rat Strain

Abstract

Chronic renal fibrosis is the final common pathway of end stage renal disease caused by glomerular or tubular pathologies. Genetic background has a strong influence on the progression of chronic renal fibrosis. We recently found that Rowett black hooded rats were resistant to renal fibrosis. We aimed to investigate the role of sustained inflammation and oxidative/nitrative stress in renal fibrosis progression using this new model. Our previous data suggested the involvement of podocytes, thus we investigated renal fibrosis initiated by doxorubicin-induced (5 mg/kg) podocyte damage. Doxorubicin induced progressive glomerular sclerosis followed by increasing proteinuria and reduced bodyweight gain in fibrosis-sensitive, Charles Dawley rats during an 8-week long observation period. In comparison, the fibrosis-resistant, Rowett black hooded rats had longer survival, milder proteinuria and reduced tubular damage as assessed by neutrophil gelatinase-associated lipocalin (NGAL) excretion, reduced loss of the slit diaphragm protein, nephrin, less glomerulosclerosis, tubulointerstitial fibrosis and matrix deposition assessed by periodic acid–Schiff, Picro-Sirius-red staining and fibronectin immunostaining. Less fibrosis was associated with reduced profibrotic transforming growth factor-beta, (TGF-β1) connective tissue growth factor (CTGF), and collagen type I alpha 1 (COL-1a1) mRNA levels. Milder inflammation demonstrated by histology was confirmed by less monocyte chemotactic protein 1 (MCP-1) mRNA. As a consequence of less inflammation, less oxidative and nitrative stress was obvious by less neutrophil cytosolic factor 1 (p47phox) and NADPH oxidase-2 (p91phox) mRNA. Reduced oxidative enzyme expression was accompanied by less lipid peroxidation as demonstrated by 4-hydroxynonenal (HNE) and less protein nitrosylation demonstrated by nitrotyrosine (NT) immunohistochemistry and quantified by Western blot. Our results demonstrate that mediators of fibrosis, inflammation and oxidative/nitrative stress were suppressed in doxorubicin nephropathy in fibrosis-resistant Rowett black hooded rats underlying the importance of these pathomechanisms in the progression of renal fibrosis initiated by glomerular podocyte damage.

Renoprotective Effects of a Highly Selective A3 Adenosine Receptor Antagonist in a Mouse Model of Adriamycin-induced Nephropathy

“…Nephrin has important effects in controlling the integrity and functions of the podocyte slit diaphragm structure ( 16 ). In a previous study, ADX induced direct toxic damage to the podocytes and loss of nephrin in urine ( 13 ). Immunohistochemical staining revealed that the numbers of nephrin-positive cells were dramatically decreased in the glomeruli of ADX-injected mice and were significantly restored by LJ1888 treatment.…”

“…ADX leads to direct toxic injury of the glomerular filtration barrier including podocytes, the glomerular basement membrane and glomerular endothelial cells. Podocyte damage induces loss of protein and nephrin in the urine ( 13 ). In order to investigate the effects of LJ1888 on podocyte injury in ADX-induced nephropathy, we checked the urinary excretion of protein and albumin.…”

“…There is a considerable body of evidence regarding oxidative stress in various kidney diseases. In ADX-induced nephropathy, oxidative stress and inflammation are important mechanisms of progressive proteinuric nephropathy leading to renal fibrosis ( 13 ). Renal tissue hypoxia induces the elevation of adenosine levels, leading to renal fibrosis ( 22 ).…”

Intestinal bacteria are necessary for doxorubicin-induced intestinal damage but not for doxorubicin-induced apoptosis

“…DOXO treatment may also result in an inflammatory response following penetration of the epithelial barrier by bacterial products, or via another distinct pathway, such as the AKT-dependent inflammation that leads to cardiomyopathy following DOXO, or the CCL2-dependent inflammation that leads to renal fibrosis following DOXO. 32,33 To elucidate these mechanisms, future investigations will evaluate epithelial permeability, as well as the role of the inflammatory response, following DOXO. We hypothesize that treatment with DOXO causes an increase in the permeability of the epithelial barrier (due to a transient induction of increased apoptosis), concomitant with increased association of enteric bacteria with the mucosa, allowing bacterial products to penetrate and induce an inflammatory response, resulting in the significant mucosal damage (and repair) observed in our studies.…”

Resveratrol Protects against High-Fat Diet Induced Renal Pathological Damage and Cell Senescence by Activating SIRT1

“…Therefore, resveratrol rescued HDF-induced inflammatory response and oxidative stress which will strongly induce renal fibrosis. [42][43][44] These results demonstrated that resveratrol can play beneficial roles both in vivo and in vitro.…”